In Amenas (Algeria), Jan. 19 (AP): In a bloody finale, Algerian special forces stormed a natural gas complex in the Sahara desert today to end a standoff with Islamist extremists that left at least 19 hostages and 29 militants dead. Dozens of foreign workers remain unaccounted for, leading to fears the death toll could rise.

With few details emerging from the remote site in eastern Algeria, it was unclear whether anyone was rescued in the final operation.

The siege at In Amenas transfixed the world after radical Islamists linked to al Qaida stormed the complex, which contained hundreds of plant workers from all over the world, and then held them hostage surrounded by the Algerian military and its attack helicopters for four tense days that were punctuated with gunbattles and dramatic tales of escape.

In the final assault, the remaining band of militants killed seven hostages before special forces killed 11 of the attackers, the state news agency said. It was not immediately possible to verify who killed the hostages. The military launched its assault to prevent a fire started by the extremists from engulfing the complex, the report said.

The seven hostages and 11 militants adds to the previous toll of 12 captives and 18 kidnappers, according to the government, but there are fears that the number of hostages killed is much higher and dozens of foreign workers from the site remain unaccounted for. Sonatrach, the Algerian state oil company running the site along with BP and Norway’s Statoil, said the entire refinery had been mined with explosives, and the process of clearing it out had begun, indicating the militants planned to blow up the complex.

Algeria has fought its own Islamist rebellion since the 1990s, elements of which later declared allegiance to al Qaida and then set up new groups in the poorly patrolled wastes of the Sahara along the borders of Niger, Mali, Algeria and Libya, where they flourished.

The militants, who came from a Mali-based group run by an Algerian, attacked the plant on Wednesday morning. Armed with heavy machine guns and rocket launchers in four-wheel drive vehicles, they fell on a pair of buses taking foreign workers to the airport. The buses’ military escort drove off the attackers in a blaze of gunfire that sent bullets zinging over the heads of crouching workers. A Briton and an Algerian — probably a security guard — were killed.

Frustrated, the militants turned to the vast gas complex, divided between the workers’ living quarters and the refinery itself, and seized hostages.